Dimethyl Disulfide (DMDS) A Methyl-Bromide Replacement Candidate. P. Robinson, R. Whitson, & T. Estes

Transcription

1 Dimethyl Disulfide (DMDS) A Methyl-Bromide Replacement Candidate P. Robinson, R. Whitson, & T. Estes

2 Natural Background Concentrations Biological 1 Human expired air: max. 0.6 μg/hr) Human expired air: max. 7ng/l) Poultry manure: 85 μg/kg Anthropogenic 1 Wastewater effluent (45 μg/l) 1/ low levels are maintained due to flux

3 Naturally Occurring in the Environment Living Organisms Salt Water Brackish Water Fresh Water Sediment Soil Atmosphere

4 Formation From Natural Processes Biogenic Atmospheric Sulfur Cycle Methionine Degradation Pathway cheese products Dimethylsulfoniopropianate (DMSP) Degradation Pathway marine bacteria

5 DMDS: An ubiquitous natural compound In plants Allium spp pea mushrooms bean (truffle, shiitake) Brassicacea spp In animal tissues milk cheese human urine In processed food animal by-products coffee bread salmon registered as a food additive to create a garlic-like taste

6 Pathways for the formation of DMDS In Brassicacea: from thiomethyl glucosinolates Glu-S (CH 2 ) n -S(O) x -CH 3 N n = 2, 3, 10 x = 0, 1, 2 mirosinase CH 3 -SO-(CH 2 ) n -N=C=S - O 3 SO Glucosinolates Isothiocyanates CH 3 -S-SO 2 -CH 3 + CH 3 -S-S-CH 3 Thiosulfonates CH 3 -S-SO-CH 3 Thiosulfinates

7 Pathways for the formation of DMDS In Allium spp. From S-methyl-cysteine sulfoxide NH 2 -CH(COOH)-CH 2 -S(O)-CH 3 S-methyl-cysteine sulfoxide alliinase CH 3 -S-SO 2 -CH 3 + CH 3 -S-S-CH 3 Thiosulfonates CH 3 -S-SO-CH 3 Thiosulfinates

8 DMDS Atmospheric Effects Ozone depleting potential (ODP) is 0 Half-life in the upper atmosphere predicted to be on the order of several hours Part of the natural atmospheric sulfur cycle with formation of acidic sulfur products

9 Important Industrial Uses of DMDS Agent used in hydrodesulfurization processes in the petrochemical industry Coke inhibiting agent used in ethylene furnaces Used as an FDA registered food additive (Sec Synthetic flavoring substances and adjuvants) for flavoring use in the minimum quantity to produce their intended effect

10 DMDS physical-chemical properties Molecular formula: C 2 S 2 H 6 Molecular weight: Appearance: yellow liquid Odor: garlic-like smell

11 DMDS physical-chemical properties Boiling point: C Flash point: 16 C Density (20 C) Henry s law constant: (20 C)

12 DMDS physical-chemical properties Koc ml/g Vapor pressure: 28.7 mm Hg (25 C) Water solubility: 3000 mg/l (25 C)

13 DMDS Mode of Action DMDS causes mitochondrial dysfunction and activation of K-ATP channels blocks the cytochrome oxydase (Complex IV) acts on K-ATP channels by an hyperpolarization

14 Acute Toxicity Profile Acute oral LD 50 - rats: mg/kg Acute inhalation LC 50 - rats: ppm ( mg/m 3 ) Acute dermal LD 50 - rabbits: >2000 mg/kg Dermal irritation: Irritant (Tox. Category III) Eye irritation: Irritant (Tox. Category III) Dermal sensitization: Non-sensitizer

15 DMDS Efficacy Weed Control

16 DMDS Efficacy Rate Response

17 % Control of Nutsedge in Peppers W/ DMDS Applied Alone Under LDPE, Rate Effect Vs. Methyl Bromide. Culpepper, Univ. Georgia, Tifton 2005 % Nutsedge control at 34 Days After Application Rates in Lbs/Acre DMDS 200 DMDS 400 DMDS 600 MeBr 400 (67:33)

18 DMDS Efficacy Application Depth

19 Effect of Injection Depth & Barrier Type on Weed Control LDPE VIF gallons/acre (79:21)

20 DMDS Efficacy Injection Shank Number

21 Nutsedge Control in Tomato, DMDS Alone, Shank Number Effect LDPE, VIF, Vs. METALIZED FILM Gilreath, Univ. Florida, Ruskin, FL 2005 Fall lb/a Counts (50 ft.) area 3-shank injection 4-shank injection LDPE VIF METAL 14 day plantback interval, weed control at 74 Days after application

22 DMDS Efficacy Barrier Type

23 Nutsedge Control in Tomato, DMDS Alone, Barrier Effect LDPE, VIF, Vs. METALIZED FILM Gilreath, Univ. Florida, Ruskin, FL 2005 Fall Counts (50 ft.) area UNTREATED 400 lb/a LDPE VIF METAL 14 day plantback interval, weed control at 49 Days after application

24 DMDS on Squash, % Nutsedge Control in Tifton; GA; Fall 2005 Mulch Type Effect, DMDS Mixture With Chloropicrin METAL (s/b) METAL (s/w) METAL Embossed (s/b) DMDS 750 (80:20) METAL Embossed (b/s) VIF (b/b) LDPE (w/w/) LDPE (w/b) Trial conducted by Dr. Stanley Culpepper; UGA REC; Tifton, GA. All treatments applied on 7/14/05. Squash were planted 27 days after fumigant applications. Evaluations at 47 days after Planting

25 Combinations of DMDS With Chloropicrin

26 Effect of Rate and Combinations With Chloropicrin on Nutsedge Control (%), Culpepper. Univ. GA, Tifton, Percent Nutsedge 97 Days After Application, LDPE Barrier 0 Alone lbs lbs. 400 (67:33) 200 lbs. 400 lbs. 600 lbs.

27 The Overall Influence of These Variables on Weed Control

28 % Control of Nutsedge in Peppers w/ DMDS + PIC Barrier Comparisons Culpepper, Univ. Georgia, Tifton 2006 DMDS 74 gal 570 lb. DMDS: 150 PIC LDPE UNTREATED

29 % Control of Nutsedge in Peppers w/ DMDS + PIC Barrier Comparisons Culpepper, Univ. Georgia, Tifton 2006 DMDS 74 gal 570 lb. DMDS: 150 PIC UNTREATED VIF

30 % Control of Nutsedge in Peppers w/ DMDS + PIC Barrier Comparisons Culpepper, Univ. Georgia, Tifton 2006 DMDS 74 gal 570 lb. DMDS: 150 PIC UNTREATED METALIZED

31 Impact of Mulch Types on Nutsedge Control of the Untreated, MeBr &DMDS Treatments; Tifton; GA; Spring 2006 % Control of Nutsedge at 72 days after application LDPE METALIZED VIF UNT DMDS 75 gal (79:21) MEBR 350 (67:33) Trial conducted by Dr. Stanley Culpepper; UGA REC; Tifton, GA. All treatments applied on 2/22/06. Holes were punched in mulch 15 days after application and peppers were planted 3 days later.

32 DMDS Crop Safety Excellent Crop Safety Plant back in 7-21 day

33 Impact of Mulch Types on Marketable Pepper Yields of the Untreated, MeBr &DMDS Treatments; Tifton; GA; Spring 2006 Number of Fruit/Plot: Harvests 1 & 2 combined LDPE METALIZED VIF UNT DMDS 75 gal (79:21) MEBR 350 (67:33) Trial conducted by Dr. Stanley Culpepper; UGA REC; Tifton, GA. All treatments applied on 2/22/06. Holes were punched in mulch 15 days after application and peppers were planted 3 days later.

34 Impact of Mulch Types on Marketable Pepper Yields of the Untreated, MeBr &DMDS Treatments; Tifton; GA; Spring 2006 Pounds of Fruit/Plot: Harvests 1& 2 combined LDPE METALIZED VIF UNT DMDS 75 gal (79:21) MEBR 350 (67:33) Trial conducted by Dr. Stanley Culpepper; UGA REC; Tifton, GA. All treatments applied on 2/22/06. Holes were punched in mulch 15 days after application and peppers were planted 3 days later.

35 Drip Vs Shank Effect

36 DMDS Drip Application Efficacy in Strawberry, Weed Biomass San Luis Obispo, CA 2005 Pacific Ag Group Application: 11/10/05. Harvest From: Jan to May WEED BIOMASS (Kg/PLOT) Untreated Control 400 lbs - Drip 200 lbs - drip DMDS Drip MB + Pic 350 lbs - shank 70 DAA

37 Effect on Additional Weed Species

38 DMDS Tomato Pacific Ag Group, Arroyo Grande, CA (Weed Counts/row) Weed Control (counts/row) DMDS Drip DMDS 400 -Drip Weed Control - 34 Days After Application Purslane Corn Spurry Lambsquarters Annual Bluegrass Nutsedge

39 DMDS Tomato Pacific Ag Group, Arroyo Grande, CA (Weed Counts/row) DMDS + Pic Drip DMDS + Pic Drip DMDS + Pic Drip DMDS alone & w/pic Weed Control - 34 Days After Application DMDS Drip DMDS 400 -Drip Purslane Corn Spurry Lambsquarters Annual Bluegrass Nutsedge

40 DMDS Tomato Pacific Ag Group, Arroyo Grande, CA (Weed Counts/row) DMDS + Pic Shank DMDS + Pic Shank DMDS + Pic Drip DMDS + Pic Drip DMDS alone & w/pic, Shank vs. drip DMDS + Pic Drip Weed Control - 34 Days After Application Purslane Corn Spurry Lambsquarters Annual Bluegrass Nutsedge

41 DMDS Efficacy Soil Borne Pathogens

42 Tomatoes, Drip Application Pacific Ag Group Greenfield, CA Sclerotinia Rot (Scleotinia sclerotiorum ) Sclerotinia #/plot Untreated 200 lbs. 400 lbs. 600 lbs. 20 Gal/A Methyl 350 lbs. Rated at harvest (119 days after application).

43 Tomatoes, Drip Application Pacific Ag Group Greenfield, CA Corky Root (Pyrenochaeta lycopersici ) scale Untreated 200 lbs. 400 lbs. 600 lbs. 20 Gal/A Methyl 350 lbs.

44 Succulent Beans & Disease Incidence France, 2003 % infected plants Rhizoctonia solani Untreated 267 lbs. 535 lbs. Methyl 446 lbs.

45 DMDS Tomato Verticillium Wilt Pacific Ag Group, Arroyo Grande, CA Number per Plot Verticillium Wilt Infected Plants days after application Untreated Control DMDS Drip DMDS 600 Drip Chloropicrin Drip

46 DMDS Tomato Verticillium Wilt Pacific Ag Group, Arroyo Grande, CA Number per Plot Verticillium Wilt Infected Plants days after application Untreated Control DMDS + Pic Drip DMDS + Pic Drip DMDS + Pic Drip Chloropicrin Drip

47 IRIS Plants with Fusarium Wilt Pacific Ag Group, Nipomo, CA Number/Plot Days After Application Untreated Control MB + Pic fb Vapam Vapam 200 lbs DMDS DMDS

48 DMDS Efficacy Soil Borne Pathogens Sclerotinia Rot Rhizoctonia Verticillium Wilt Fusarium Wilt Pythium?

49 DMDS Efficacy Nematodes

50 Soil Borne Pest Control in Tomatoes Shank Application on 3-mar, 2004 Pliant High Barrier Mulch (Black) J. Gilreath, Univ. FL Bradenton Number of Stunt Nematodes (Tylenchorhynchus sp. ) 4 Untreated Nematodes/100cc of soil Jun 200 lb/a 400 lb/a 600 lb/a 300 lb/a Midas is methyl iodide:chloropicrin (67:33)

51 Root Gall Severity in Tomato (0-10 Scale) J. Noling, Univ. of Lake Alfred, FL 2005, fall <---Best - Worst---> Meloidogyne sp. Alone Untreated DMDS 150 DMDS 300 DMDS 450 DMDS 600 Telone 26 GPA MeBr 400 (67:33)

52 DMDS Tomato Pacific Ag Group, Arroyo Grande, CA Number per Cubic Centimeter Paratrichodorus sp. Stubby Root Nematode - 67 DAT - Compared to UTC Untreated Control DMDS Drip DMDS 600 Drip DMDS + Pic Drip DMDS + Pic Drip DMDS + Pic Drip DMDS + Pic Shank DMDS + Pic Shank Chloropicrin Drip Vapam - 75 gal - Drip Inline 20.5 gal - Drip Midas + Pic Drip

53 DMDS Tomato Pacific Ag Group, Arroyo Grande, CA Number per Cubic Centimeter Pratylenchus spp. Root Lesion Nematode - 67 DAT Untreated Control DMDS Drip DMDS 600 Drip DMDS + Pic Drip DMDS + Pic Drip DMDS + Pic Drip DMDS + Pic Shank DMDS + Pic Shank Chloropicrin Drip Vapam - 75 gal - Drip Inline 20.5 gal - Drip Midas + Pic Drip

54 DMDS Efficacy Against Citrus Nematode Application Via Buried Drip at 8 Depth. Radewald, CA Number of nematodes recovered from bags buried at each depth "depth 10"depth 18"depth Untreated 290 lb/a-no barrier 581 lb/a-no barrier 141 lb/a-no barrier 290 lb/a-w/ldpe 581 lb/a-w/ldpe

55 DMDS Efficacy Nematodes Stunt Root Knot Stubby Lesion Cyst?

56 DMDS Registration Submission for an EUP program August, 2006 Currently in science review Submission for Section 3 registration 1 st quarter, 2007

57 DMDS DMDS effective in shank and drip applications (pure and 95% EC formulations) On nematodes (200/400 kg.ha -1 ) On fungi (400/600 kg.ha -1 ) On weeds (600 kg.ha -1 ) Soil diffusion is very good Effectiveness is higher using VIF or equivalent films DMDS in combination with chloropicrin demonstrates excellent results, lower rates DMDS is a viable candidate for replacement for Methyl Bromide

58 Thank you!